Delta Tau Geo MACRO, User Manual And Reference Manual

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Geo MACRO Drive User Manual
86 Setting Up Turbo Motor Operation
that these readings may appear noisy. Observe the base value underneath the noise.) If M105 is positive
and M106 is negative, the sign of the PWM commands matches the sign of the ADC feedback values. In
this case, the Turbo PMAC phase angle parameter I172 must be set to a value greater than 1024 (1365 for
a 3-phase motor).
If M105 is negative and M106 is positive, the sign of the PWM commands is opposite that of the ADC
feedback values. In this case, I172 must be set to a value less than 1024 (683 for a 3-phase motor).
Make sure your I172 value is set properly before attempting to close the digital current loops on Turbo
PMAC. Otherwise positive feedback will occur, creating unstable current loops which could damage the
amplifier and/or motor.
If M105 and M106 have the same sign, the polarities of the current sense circuitry for the two phases is
not properly matched. In this case, something has been mis-wired in the drive or between Turbo PMAC
and the drive to give the two phase-current readings opposite polarity. One of the phases will have to be
fixed.
Do not attempt to close the digital current loops on Turbo PMAC until the polarities of the current sense
circuitry for the two phases have been properly matched. This will involve a hardware change in the
current sense wiring, the ADC circuitry, or the connection between them. As an extra protection against
error, make sure that Ixx57 and Ixx58 are set properly for I
2
T protection that will shut down the axis
quickly if there is saturation due to improper feedback polarity.
Troubleshooting
If not getting the current readings that are expected, probe the motor phase currents on the motor cables
with a snap-on hall-effect current sensor. If the current is not seen when commanding voltages, check for
phase-to-phase continuity and proper resistance when the motor is disconnected.
Testing PWM and Current Feedback Operation
WARNING:
On many motor and drive systems, potentially deadly voltage and current levels
are present. Do not attempt to work directly with these high voltage and current
levels unless fully trained on all necessary safety procedures. Low-level signals on
Turbo PMAC and interface boards can be accessed much more safely.
Usually, in setting up a direct PWM interface there is no need to execute all of the steps listed in these
sections (or the Turbo Setup program will do them automatically). However, the first time this type of
interface is setup or there are problems, these steps will be of assistance.
For safety reasons, all of these tests should be done with the motor disconnected from any loads. All
settings made as a result of these tests are independent of load properties, so will still be valid when the
load is connected.
Before testing any of Turbo PMAC’s software features for digital current loop and direct PWM interface,
it is important to know whether the hardware interface is working properly. PMAC’s M-Variables are
used to access the input and output registers directly. The examples shown here use the suggested M-
Variable definitions for Motor 1.
Purpose
The purpose of these tests is to confirm the basic operation of the hardware circuits on PMAC, in the
drive, and in the motor, and to check the proper interrelationships. Specifically:
•
Confirm operation of encoder inputs and decode
•
Confirm operation of PWM outputs
•
Confirm operation of ADC inputs
•
Confirm correlation between PWM outputs and ADC inputs